In quarries or construction sites, a plurality of dump trucks are operated in order to carry the excavated materials (rocks, earth, sand, etc.). Each dump truck travels on a traveling lane to and fro between the loading site and the unloading/dumping site. If the road surface of the traveling lane for the dump trucks has irregularities, the dump trucks suffer influences such as excessive fuel consumption and tire wear, as well as giving discomfort to the driver. In order to resolve such problems, a road surface repairing system for detecting and repairing the road surface irregularities has been proposed (see Patent Document 1, for example).
In the road surface repairing system described in the Patent Document 1, a millimeter wave sensor is arranged at the front of each dump truck. The millimeter wave sensor detects the distance from the installation position of the millimeter wave sensor to the road surface of the traveling lane by irradiating the road surface with a transmitted wave and receiving a reflected wave from the road surface. A control unit installed in each dump truck judges the irregularities of the road surface based on the detected result by the millimeter wave sensor. Specifically, the distance from the installation position of the millimeter wave sensor to the road surface of a flat road/land having no irregularities is defined as a reference value. The control unit judges that the road surface on which the dump truck is traveling has significant irregularities needing repair if the distance detected by the millimeter wave sensor is longer or shorter than the reference value by a prescribed value or more.
When the aforementioned control unit of the dump truck judges that the road surface has significant irregularities needing repair, the control unit stores the position of the dump truck calculated by a GPS device as the position of the damaged road surface. The control unit also generates the traveling path (locus) of the dump truck based on the position record of the dump truck. The control unit of each dump truck transmits the road surface irregularity position information and the traveling path information to a management station.
A control unit of the management station receives the road surface irregularity position information and the traveling path information from the dump trucks and generates repair map data, indicating the positions of the traveling lanes (road surfaces) needing repair, based on the received information. Then, the control unit of the management station transmits the generated repair map data to road repair vehicles (e.g., motor graders). A control unit installed in each road repair vehicle receives the repair map data from the management station and displays the repair map data on an indicator. Consequently, the drivers of the road repair vehicles can drive the road repair vehicles to the positions needing repair displayed on the indicators and carry out the repair work at the positions.